It's also located here: http://www.wowinterface.com/download...eModifier.html

Woops, ofcourse I would've preferred a WoWI link, but I google'd it and just robotic arm clicked on the first link which was curseforge :)

I download all addons that I need, than I start with Actionbars, too. I usually don't do something with the Minimap. The panels after the bars (Kgpanels) and then I look (usually) for oUF Unit Frames, because they don't use many memory. The chat, bag, and something more at last.:)

I'm quite surprised no one has said "I get a pen and paper" - it seems to be logical!

I generally take the class and spec I'm going to play, sum up what I need to know while playing it, then develop addons around that need.

I normally start with the unitframes, then cooldowns, buffs, minimap etc

Like this:

http://rf.shkm.net/category/features...ent-interface/

Not intended to be a plug, it's my answer to the question :). I do things a little different nowadays, though.

I usually have a rough picture in my head on how I want my UI and what I want to achieve with the UI.

Then if it's a clean addons isntall I start with disabling or hiding everything I don't need (actionbars, some UF's, .. all the clutter around minimap, ..) so my screen is as empty as possible.

before I start I generally put the chat in the bottom left corner, make sure I have a clean minimap and place it where I want it, and place my buffs at the desired place (tho not fully configured yet)

Then I just start doing whatever I feel like doing at that time. Tho the main focus are always the unit frames as I find those the most important part of the UI (I'm a tank).

I build up everything in segments. For example, my unit frame is together with my cooldown actionbar, my buff bar for procs, short duration buffs etc, my castbar and thigns like that.

While my target frame is together with my threatbars, ToT frame, short duration boss timers, etc.

After that comes party/raid which as a tank aren't that important anyway.

Then I basically jsut follow my feeling on what I should change so it would benefit my playstyle as much as possible, mostly taking a few weeks before my raw sketch of the UI finally has a "completed" version. Which can be quite different from the image I first had in my head.

I think of what i want to achive with that interface and also for wich class it's ment, pvp and pve are very different from eachother and most of the time requires a diff setup for my interface. I useally start with my castbar(how silly as it seems) and build thing's around it cause i love to have my castbar very visually.

I personally prefer interfaces that keep themselves in the same basic feel as the default interface does: at least three action bars visible on the bottom of the screen, action bars on the right side, unit frames somewhere easily visible and minimap in the top right portion of the screen. But I'm also very focused on the general style and feel of the interface I use. Not that many of the really commonly used visual styles for design interface--like the minimalistic setups, pixel fonts, gradient backgrounds, bottom screen dashboards, and so on--really appeal to me all that much. I understand and respect the fact that most interface designers aren't exactly artists and try to make the best of what they're able to create, but personally it's a world of design choices that personally I just don't like.

Because of both of the above, I'm currently enjoying myself with Zork's Roth UI, which I've done some modifications of to suit my own preferences. It has the base design and setup that I like playing with, and quite honestly it looks kick-ass.

Generally, it depends on which class I'll play.

Usually I start off with a set list of addons I always use:
- oUF
- Dominos
- oChat
- oMirrorBars
- ...

Then I create a rough draft on paper (yes, I actually use paper, I like the tactile sensation, to quote Freya/Anise from SG1), and get working on which texture I like for my UFs, castbars etc. I pick my fonts (I have a list of several I like).
Then positioning of the UFs and chatboxes. My minimap usually remains in the same spot, though I am considering changing that too now. Then I get the rest going.

I have a tendency to always place my actionbars centered at the bottom. Because I like seeing my HP as well as targets, I am stuck with my UFs centered as well.

Basically, I ask myself which info do I need to see when raiding, what is info I may need/want easily but don't need straightaway. And then what is occasional info (eg gathermate)? Based on that I review my draft. I set it up, go over it while raiding. If it doesn't work I review it again.. etc

Apologies for the lack of coherence, I am drowsy at the moment.